Chrome: BitTorrent clients aren't hard to come by, but if you don't want to deal with extra software, OneClick is a Chrome extension that downloads torrents directly in your browser.

With OneClick installed you simply have to click on a torrent file and it will start downloading the torrent contents directly with Chrome. I had mixed luck with getting OneClick to work. The extension's main page suggests you try a Counting Crows official torrent and that worked fine, but OneClick didn't recognize a few different Linux torrents. If you le OneClick sit for a while it will usually eventually trigger the download. OneClick doesn't offer the features of a dedicated BitTorrent client, but it might come in handy for the occasional download.